Transfer and grinding apparatus

ABSTRACT

Apparatus for transferring a rectangular or generally elliptical viewing panel for a cathode or television picture ray tube between a panel receiving and pickup station and a grinding station, and for flat grinding, at the grinding station, the annular sealing edge of the skirt portion or open end of the viewing panel in preparation for hermetic sealing of the sealing edge of the panel to the complemental sealing edge of a funnel member for the tube, and then returning the ground panel to the pickup station.

United States Patent [191 Noll [11] 3,849,944 [451 Nov. 26, 1974 TRANSFER AND GRINDING APPARATUS [75] Inventor: Burton A. Noll, Painted Post, NY.

[73] Assignee: Corning Glass Works, Corning,

[22] Filed: Nov. 5, 1973 [21] Appl. No.: 412,665

[52] US. Cl 51/215 CP, 51/227 R, 51/235 [51] Int. Cl B24b 47/02 [58] Field of Search 51/109 R, 124 R, 215 R,

51/215 AR, 215 HM, 215 CP, 215 H, 227 R, 235, 283', 269/321 T; 214/1 BC [56] References Cited UNITED STATES PATENTS 2,948,988 8/1960 Stutske 269/321 T 2,974,811 3/1961 Dammertm, 214/1 BC 3,161,753 12/1964 Schmick 214/1 BC Reinwall 51/227 R X Hillman 214/1 BC Primary Examiner-Al Lawrence Smith Assistant Examiner-Nicholas P. Godici Attorney, Agent, or FirmCharles W. Gregg; Clarence R. Patty, Jr.

[ 5 7 ABSTRACT Apparatus for transferring a rectangular or generally elliptical viewing panel for a cathode or television pic ture ray tube between a panel receiving and pickup station and a grinding station, and for flat grinding, at the grinding station, the annular sealing edge of the skirt portion or open end of the viewing panel in preparation for hermetic sealing of the sealing edge of the panel to the complemental sealing edge of a funnel member for the tube, and then returning the ground panel to the pickup station.

8 Claims, 9 Drawing Figures PATENTLmvzslsm SHEET 10$ 4 3,849,944

PATENTE HUVZSISM 4,

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PATENIEL 3.849.944

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HUDC FC3 HIOV F 53 HPDV T T $2 I J II W2 N W CLLFSI F52 I-FROM I W FLUID PRESSURE I 5 SOURCE W 5T WN I I HM I I I m ..To VACUUM 34 SOURCE M FCI 6! To VACUUM CHUCK VC TRANSFER AND GRINDING APPARATUS BACKGROUND OF THE INVENTION In the fabrication of a rectangular glass picture tube for a polychromatic television receiving set for example, a viewing panel having a dependent skirt portion with an annular sealing edge is sealed along such edge to a complemental annular edge of a funnel member for the picture tube, .such sealing being performed by use of a sealing glass frit deposited on the surface of one or both of said annular edges. Said panel and funnel member are disposed with the annular edges in a complemental facing relationship with each other and are sealed to each other along said sealing edges by subjecting the panel and funnel member to a heat cycle to soften said frit while urging such components towards one another to press the frit and thereby spread the frit over the entire surface of each such sealing edge. In such a seal, in order that voids therein may be prevented to the extent possible and a substantially optimum hermetic seal attained between said annular edges, it is highly desirable or even necessary that the surfaces of the annular edges be as flat as possible, that is, that all areas of the surface of each annular edge lie in the same plane. Due to the relatively high voltages at which picture tube in poly-chromatic television sets are operated and the high degree of evacuation of such tubes, said optimum hermetic sealing of the members of the tubes to each other is sought and, to such end, said surfaces of the annular sealing edges of the tube members are precisely ground to produce said flat surfaces. It is, accordingly, an object of the present invention to provide an apparatus for automatically transferring a viewing panel or panel member for a rectangular cathode ray or television picture tube between a pickup station and a grinding station, and an improved apparatus at such grinding station for flat grinding the annular sealing edge of the viewing panel or panel member. With a few changes, the apparatus may be suitably modified for handling and flat grinding the annular sealing edge of a funnel member for the cathode ray or picture tube.

Other objects and characteristic features of the invention will become apparent as the description proceeds.

SUMMARY OF THE INVENTION In practicing the invention disclosed there is provided an even number, such as four for example, of grinding wheels or disks whose flat circular grinding faces are rotated in a common horizontal plane with the peripheral edge of each grinding disk or wheel being equally adjacent such edges of two of the other disks or wheels and with the adjacent ones of the wheels being rotated in opposite directions. A viewing panel whose sealing edge is to be ground is precisely positioned at a pickup station with the aid of a positioning device or jig, and a vacuum chuck, which is initially centered over the face plate of a panel so position, is activated downwardly to contact the face plate of the panel and effect pickup thereof. The chuck is then moved or swung in or through a horizontal arc to correspondingly move the supported panel and center it over the center point of said horizontal plane of said grinding wheels or disks. The chuck is rotated and lowered to correspondingly rotate and lower the panel until the sealing edge of the panel rests on the grinding faces of the grinding wheels which may rotate continuously during a cycle of grinding operations. The desired grinding operation is thereby performed on said sealing edge. Downward force may be applied to the panel during the grinding operation and, upon the completion of such operation, the chuck is again raised and rotation of the chuck is terminated. The chuck may then be moved or swung in a manner reverse to that first described and the panel returned to the pickup station where vacuum to the chuck is terminated to release the panel in preparation for similarly handling of another panel and grinding the sealing edge thereof.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a top plan view of the apparatus embodying the invention;

FIG. 2 is a front elevational view of part of the apparatus of FIG. 1, such view being taken generally along line 2-2 of FIG. 1;

FIG. 3 is an elevational view of an upper part of the apparatus of FIG. 1, such view being taken generally along line 3-3 of FIG. 1;

FIG. 4 is an enlarged sectional view taken generally along line 4-4 of FIG. 3;

FIG. 5 is an elevational view of a lower part of the apparatus of FIG. 1 with a portion of such apparatus being broken away to cross-sectionally illustrate some details of the apparatus;

FIG. 6 is an enlarged sectional view taken generally along line 66 of FIG. 3;

FIG. 7 is an enlarged view of a portion of the apparatus of FIG. 3 with part of such apparatus being broken away to illustrate details thereof;

FIG. 8 is an enlarged sectional view taken generally along line 88 of FIG. 7; and

FIG. 9 is a diagrammatic or schematic illustration of a control system employed in conjunction with the other apparatus of the invention.

Similar reference characters refer to similar parts in each of the FIGS. of the drawings.

PREFERRED EMBODIMENT OF THE INVENTION Referring to the drawings in detail, there is shown in FIG. 1 an apparatus 10 embodying the invention and including, at an article or panel grinding station, a tub 14 (FIG. 5) whose lower surface rests on and is secured to the upper annular surface of a suitable support 11 whose lower surface rests on a platform 12 resting on a conventionally illustrated floor or other support base 13. One side of tub l4 and support 11 are partially broken away (FIG. 5) to expose some of the apparatus contained or enclosed in such tub and support, part of such apparatus being shown in cross-section for a better understanding thereof.

Tub 14 has a sloping bottom 14a from which extend upwardly relatively large diameter bosses, such as 15 (FIG. 5) each of which embodies a bushing, such as 16, which fits relatively snugly in the upper end of its respective boss and is secured thereto by a plurality of bolts such as 17. Tub I4 is intended to catch expended slurry which may be used in the grinding operations of the invention. The means or conduits for providing slurry to the grinding apparatus are not shown in the drawings since such conduits or means do not, per se,

form part of the present invention and the provision of slurry for grinding operations is well known in the art. However, it is pointed out that tub 14 embodies in the lower most part of the sloping bottom thereof a suitable sump 14b (FIGS. 1 and 5) leading to a drain pipe 14c through which expended slurry may flow from the tub to a reservoir or waste facilities which are also not shown.

There is also shown in FIG. 5 a gear motor GMl having a vertically extending output shaft 18 to the upper end of which is keyed, in any convenient manner and in a rotatably driven relationship therewith, a grinding wheel or disk 21. Output shaft 18 extends upwardly from gear motor GMl through a sleeve member such 22a, such arrangement being similar to that shown and discussed for grinding wheel or disk 21 and, therefore, for purposes of simplification of the drawings, not being shown in detail therein.

It is expedient to point out at this point in the description that there are, preferably, four rotatably supported grinding wheels or disks 21 through 24 employed (FIG. 1), the centers of such grinding wheels or disks geometrically coinciding with the four comer points of a square and the grinding faces 23a and 24a of disks or wheels 23 and 24 being similar to the faces of wheels or disks 21 and 22. Thus, the wheels or disks 21 through 24 each have a flat upwardly disposed circular grinding face 21a through 24a, respectively, of equal diameters and extending in a common horizontal plane, the wheels or disks being radially symmetrically disposed about an axial centerline AA (FIG. 5) vertical to such plane, such centerline intersecting, at a point C (FIG. 1), one end of a first circularly arcuate path B-C (FIG. 1) extending horizontally from a selected point B on the upper horizontal surface 300 of an upper plate 30b of a platform 30 (FIGS. 1 and 2) to be hereinafter discussed. It will be understood that each grinding wheel or disk 21 through 24 has a respectively associated gear motor (GMl through GM4, respectively) each of which is similar to that discussed in detail in conjunction with wheel or disk 21. As hereinafter further discussed in an operational example of the invention, adjacent ones of the wheels or disks are rotated by their respective gear motors, in opposite directions during a grinding operation. It is further pointed out that the peripheries of the grinding wheels or disks are of the same abrasive material as the faces thereof, and

that the diameters of the grinding wheels and the spacing of such wheels from each other, is selected such that each grinding face 21a through 240 will contact all points on the sealing edge of a rotating viewing panel (see panel pin FIGS. 1 and 5) when such edge rests on such grinding faces with the vertical centerline of the face plate portion of the panel coinciding with said axial centerline A--A extending vertical to the plane of said grinding faces. This will also be discussed hereinafter'in an operational example of the invention.

Referring further to FIGS. 1 and 2, taken in conjunction with FIG. 5, there is shown, at the left hand side of FIG. 1, the previously mentioned platform 30 which includes a relatively rigid base plate 30a and said upper I plate 30b, such upper plate having a relatively smooth upper surface 300 and being secured to said base plate. Plate 30a is supported by a pair of sloping legs 31 and 32 having first ends secured to the bottom or lower surface of the base plate (FIGSv 1 and 2) and second ends secured to the upper surface of platform 12 (FIG. 5). Platform 30 is preferably, but need not necessarily be, supported such that the upper horizontal surface 300 of upper plate 30b thereof extends generally in the same plane as said common horizontal plane of the faces of said horizontal grinding wheels or disks 21 through 24. A jig or panel positioning device 33 (FIGS. 1 and 2) is secured to upper surface 300 of upper plate 30b of platform 30 adjacent the rear and right hand edges of such platform (viewing FIG, 1) such jig or device comprising a horizontally extending plate 33a whose lower surface rests on said surface 300. Plate 33a embodies a semicircular cut-out defined by a circularly arcuate vertical surface 33b, the curvature of such surface having a horizontal radius corresponding to the largest radius of the generally elliptical annular sealing edge of a TV picture tube viewing panel (see panel P in FIG. 2) which such sealing edge is to be flat ground by the grinding wheels, or disks of the apparatus of the invention. Said cut-out is embodied in plate 33a of jig 33 such that the geometric center of said circularly arcuate surface 33b, that is, the geometric center of said semicircular cut-out, coincides with the previously mentioned selected point B on said upper surface 300 of plate 30b of platform 30. The purpose of such arrangement will become apparent later in the description but it is here pointed out that platform 30 is considered to be located at an article or panel receiving and pickup station.

Referring further to FIG. 5, there is shown the lower part of relatively large diameter column or shaft 35 whose lower end 35a is rotatably supported in and by a suitable bearing 36 secured to the upper surface of platform 12 as shown in FIG. 5. Shaft 35 extends up wardly from said bearing 36 and through a bushing 37 secured in a circular sleeve-type support member 38 which extends snugly through a circular hole embodied in a support plate 34, such sleeve-type support member being secured to support plate 34 as by being welded thereto for example. Support plate 34 is, in turn, welded to tub 14 for support of such plate. Column or shaft 35 extends further upwardly from said bushing 37 and sleeve-type support member 38, and there is welded to the upper end 35b of column or shaft 35 one end of a horizontally extending arm 39 (FIGS. 1 and 3) including a rigid flat top plate 40 and a plurality of vertical and horizontal bracing and support plates 41, 42, 43, 44, 45, 46, 47 and 48 which are also welded to said column or to each other as best illustrated in FIG. 3. It should be pointed out that the aforesaid bearing 36, which is rotatably supporting shaft or column 35 at said lower end 35a thereof (FIG, 5) is positioned on and secured to the upper surface of platform 12, and that sleeve-type support member 38 is 'positioned on support plate 34 so that the vertical centerline of shaft 35 is equidistantly located from said axial centerline AA (FIG, 5) extending vertically to the plane of said grinding faces of grinding wheels or disks 21 through 24 and from a line extending vertically through said selected point B (FIG. 1) that is, through said geometric center of said circularly arcuate surface 33b of plate 33a of jig 33, that is to say, through the geometric center of said semicircular cut-out embodied in plate 33a of jig 33 (FIG. 1). Column or shaft 35 and the apparatus supported and carried thereby are considered to be located adjacent to said article or panel receiving and pickup station and said grinding station.

A gear motor HM (FIGS. 1, 3 and 7) is bolted to a plate 49 welded to the upper edge of a hollow motor support member 50 whose lower edge is welded to the upper surface of said top plate 40 of arm 39 adjacent the second end of such arm. Plate 49, support member 50, and gear motor HM are located or positioned on said upper surface of said top plate 40 so that the vertical centerline of downwardly extending output shaft 51 (FIG. 7) of the gear motor is a distance from said centerline of shaft or column 35 equal to the previously mentioned distance of the centerline of said column from said vertical axial centerline AA (FIG. 5) of said grinding wheel faces and said line extending vertically through said selected point B, that is, through said geometric center of said semicircular cut-out embodied in plate 33a ofjig 33 (FIG. 1). Said output shaft 51 extends downwardly through a suitable hole or opening 49a provided in said plate 49 and thence into the hollow 50a of motor support member 50 as illustrated in FIG. 7.

There is shown in FIGS. 3 and 6 a vacuum chuck support assembly 55 comprising a generally cylindrical longitudinal hollow housing 56 having a flange portion 56a (FIG. 3) by which such housing is secured in a ver tical position to the outer face of previously mentioned support plate 48 secured to and depending from the ends of bracing plates 42 and 43 attached to shaft 35. A longitudinal hollow cylindrical sleeve member 58 (FIG. 6) is disposed in hollow 56b of housing 56 and snugly extends through the inner races of upper and lower ball bearings 59 and 60, respectively, whose outer races are disposed or secured in enlarged upper and lower bore portions 560 and 56d, respectively, of hollow 56b in housing 56. A rotational drive shaft 61 extends snugly but vertically slidable through bushings 62 and 63 provided in enlarged upper and lower bore portions 58a and 58b, respectively, of sleeve member 58.

A vertical longitudinal slot 580 is provided in the wall of sleeve member 58 between said enlarged upper and lower bore portions 58a and 58b of such sleeve member, and sleeve member 58 is keyed to drive shaft 61 for rotation therewith, such keying being provided by a suitable key member 64 which fits snugly but vertically slidable in said slot 58c and in a short vertical shaft 61. Key member 64 is secured in said channel 61a by an allen screw 65 extending through the key member and screwed into a threaded hole 61b provided in shaft 61. By such arrangement, rotation of shaft 61 imparts driven rotation to sleeve member 58 which rotates in ball bearings 59 and 60 while shaft 61 is vertically movable in bushings 62 and 63 in sleeve member 58 and, thus, within said sleeve member. The outer periphery of the upper end of sleeve member 58 is threaded and a lock nut and washer 66 and 67, respectively, are disposed over such end and nut 66 is tight ened down so that such washer bears firmly against the upper rim of the inner race of ball bearing 59. Sleeve member 58 at its lower end rests on the upper rim of the inner race of ball bearing 60 and such sleeve member is thus vertically supported within the hollow or bore 56b of housing 56 as illustrated in FIG. 6.

a A vacuum rotary union RU (FIG. 6) houses a pair of upper and lower ball bearings 77 and 78, respectively, the outer races of such bearings being disposed in upper and lower enlarged end bore portions 69 and 70, respectively, of bore 79 of union RU. A bushing 72 is also housed in rotary union RU and extends snugly through the inner races of said bearings 77 and 78 for rotation therewith and the center portion of bore 79 of union RU in a relatively snug but rotatable relationship therein. Drive shaft 61 extends snugly through the bottom of bushing 72 and such bushing is keyed to said shaft, for rotation therewith, by a set screw 73 extending through a hole 72a in bushing 72 and screwed into a suitably threaded hole 61d provided in shaft 61. Shaft 61 embodies a longitudinal vacuum passage 61c extending through the center of a greater portion of the shaft and opening out of the bottom end thereof as hereinafter further discussed. Such passage connects, adjacent its upper end, with a horizontal passage 6le extending horizontally through shaft 61, both ends of such passage opening through the outer periphery of shaft 61 and connecting with a pair of holes 72b and 720 extending through the wall of bushing 72. Rotary union RU embodies in the inner wall of the center portion thereof an annular channel 76 which connects with said holes 72b and 720 in bushing 72. Channel 76 also connects with a hole 84 extending horizontally through said center portion of rotary union RU and one end of a flexible conduit FC1 is suitably connected with said hole 84 to at times supply vacuum or negative pressure therethrough to said holes 72b and 720, thence to said annular channel 6le and, thereby, to passage 610 in shaft 61. This will be further discussed hereinafter in conjunction with FIG. 9 of the drawings and an operational example of the invention given in conjunction with such drawing figure. It is pointed out that suitable annular hermetic seals such as 80 through 83 are provided about shaft 61 and the outer periphery of bushing 72 to prevent vacuum leakage to the extent possible. Rotary unions such as RU are well known in the art.

An annular member 85 is disposed adjacent the upper end of rotary union RU and embodies a ball bearing 86 with the outer race of such bearing fitting snugly within the bore 85a of member 85. (See also FIG. 4). Shaft 61 extends through the inner race of bearing 86 in a snug and rotatable relationship there with and a suitable lock washer and nut 87 and 88, re spectively, surround shaft 61 and bear against the upper annular surface of the inner race of bearing 86 for support of shaft 61 in its aforesaid surrounding bushings such as 62, 63 and 72. Member 85 includes on its outer periphery an outwardly extending portion 85a (FIGS. 3, 4 and 6) of a lesser vertical thickness than the remainder of such member 85 and having an outer periphery generally that of a quarter of a circle. The upper end of a vertical rod or shaft 90 extends snugly through'a suitable hole b, in said portion 85a and such shaft is held in such hole by a set screw 91 screwed through a threaded hole 850 in said portion 85a of member 85. Rod or shaft extends downwardly from said portion 85a of member 85 and snugly through a hole 92a extending vertically through a support member 92 which is bolted to the outer periphery of rotary union RU. (See FIGS. 3 and 6). Shaft or rod 90 is held in said hole 92a as by a set screw 93 screwed through a suitably threaded hole 92b in said member 92. Shaft or rod 90 extends further downwardly through a pair of bushings 94 and 95 in a snug but slidable relationship therewith. Such bushings 94 and 95 are securely held in a hole 96a extending vertically through an outwardly extending integral part 96 of the aforesaid housing 56 of the previously mentioned vacuum chuck support assembly 55. By such arrangement, rotary union RU and member 85 thereabove are held against rotation thereof while permitting vertical movement of such union and member by vertical sliding movement of rod or shaft 90 within said bushings 94 and 95.

Referring further to FIGS. 1 and 3, a motor means,

comprising a pressurized fluid cylinder HUDC and associated piston rod PR2 is secured to support plate 47 fastened to the right hand end (viewing FIG. 3) of arm 39, and the lower end of said piston rod PR2 extends snugly through a hole 850 (FIG. 4) extending vertically through said portion 85a of member 85. Said lower end of piston rod PR2 is threaded and is secured to portion 85a of member 85 by an upper nut 102 screwed on to the threads on the piston rod FIGS. 3 and 4 and firmly contacting the upper surface of said portion 85a, and a lower nut 103 and lock washer 104 screwed onto piston rod PR2 and into firm contact with the lower surface of said portion 85a (FIG. 3). Flexible conduits FC2 and FC3 are connected to the lower and upper ends, respectively, of cylinder HUDC (FIGS. 1 and 3) and piston rod PR2 is actuated upwardly and downwardly by pressurized fluid supplied over conduits FC2 and FC3, respectively, to the lower and upper ends, respectively, of cylinder HUDC. This will be discussed further hereinafter in an operational example of the invention set forth in conjunction with FIG. 9.

Referring to FIG. 7, taken in conjunction with FIGS. 3, 6 and 8, the lower end of previously mentioned output shaft 51 of gear motor HM extends into a hollow 106a axially embodied in the enlarged upper end of a connecting rod 106 and such rod is keyed to output shaft 51 for rotation thereby, such keying being effected by a key 107 inserted in cooperative facing keyways 51a and 106b embodied in output shaft 51 of gear motor HM and in connecting rod 106, respectively. Connecting rod 106 extends downwardly through a hole 40a embodied in plate 40 of arm 39 and into the bore 110a of a connecting sleeve 110. The upper end of previously discussed drive shaft 61 extends into the lower end of bore 110a of connecting sleeve 110 and is keyed to such sleeve for rotation thereby. Such keying is effected by a key 112 (FIGS. 6 and 7) inserted in cooperative facing keyways 61f and 110b embodied in the upper end of shaft 61 and the lower end of sleeve 110, respectively. There is embodied in the longitudinal wall of sleeve 110, three vertical slots 110e, 110d, and 110e (FIG. 8) through which extend allen head shoulder screws 114, 115 and 116, respectively, such screws being screwed into cooperatively threaded holes 106b, 1060 and 106d, respectively, embodied in connecting rod 106 at flat surfaces 1062, 106f, and 106g, respectively, on the periphery of such rod adjacent the lower end thereof. By such arrangement driven rotation of rod 106 by output shaft 51 of motor HM imparts driven rotation to sleeve 110 and, thereby, to drive shaft 61.

Returning to FIGS. 1 and 5, there is shown securely attached to the outer periphery of column or shaft 35, which, as previously mentioned, is considered to be cated adjacent the aforesaid article or panel receiving station and the aforesaid article or panel grinding station, a clamping member 120 (FIG. 5) to the outer periphery of which there is secured, as by welding thereto for example, a pair of upper and lower outwardly extending crank arms 121 and 122, respectively. A motor means including a pressurized fluid cylinder HIOC and associated piston rod PR1 is provided and one end of such cylinder is pivotally connected to an outwardly extending arm 124a of a support member 124 (FIG. I) secured as by bolts such as 125 to the lower surface of previously mentioned support plate 34. The otherwise free end of piston rod PR] of cylinder HIOC is connected to one end of a short connecting rod 123 whose second or head end extends between said crank arms 121 and 122 adjacent the ends thereof. Said head end of rod 123 is pivotally connected to said crank arms by a headed pivot pin 126 which extends downwardly through a suitable hole embodied in said second or head end of connecting rod 123 and through cooperative and suitable holes provided in said crank arms adjacent said ends thereof. Pivot pin is held in said holes by a cotter key 127 in the manner well known in the art. Flexible conduits FC4 and FCS connect with the left and right hand ends, respectively, of cylinder HIOC (viewing FIG. 1). By such arrangement column or shaft 35 may be rotated through a 72 degree arc of rotation in clockwise and counterclockwise directions (viewing FIG. 1) accordingly as pressurized fluid is supplied over conduits FC4 and FC5, respectively, to cylinder HIOC. Such actuation or rotation of shaft 35 correspondingly moves arm 39 and, thereby, vacuum chuck support assembly 55 so that the center of drive shaft 61 moves through previously mentioned are B-C (FIG. 1) in clockwise and counterclockwise directions corresponding to the rotation of shaft 35. This will be further discussed hereinafter in the operational example of the invention set forth in conjunction with FIG. 9 of the drawings.

Referring further to FIG. 5 of the drawings, there is shown a vacuum chuck VC which is connected to the lower end of drive shaft 61 and is supported by such shaft. The aforesaid vacuum passage 61c embodied in shaft 61 at times supplies vacuum or negative pressure to vacuum chuck VC as hereinafter discussed in the operational example of the invention. The details per se of vacuum chuck VC form no part of the present invention but such vacuum chucks are well known in the art. Chuck VC may, for example, be a vacuum chuck such as the vacuum chuck 11 shown and described in copending application, Ser. No. 396,751, filed Sept. I3, 1973 by Burton A. Noll and assigned to the same assignee as the present application. The similarity between the vacuum chuck 11 of such copending application and the vacuum chuck VC of the present application will be readily apparent from a brief comparison of FIG. 5 of the present application with FIG. 2 of said copending application. However, vacuum chuck VC in the present application is shown in FIG. 5 as including an annular cover 130 of a flexible material, such as rubber for example, such cover being secured circumferentially about an upper part of chuck VC by a pair of upper and lower clamping bands 131 and 132, respectively, surrounding said cover and tightened thereabout by associated clamping screws 131a and 132a, respectively. It is pointed out that shaft 61 and screw 133 shown in FIG. 5 of the drawings of the present application may be considered to correspond, respectively, to shaft 38 and one of the screws such as 39 of FIGS. 1 and 2 of said copending application.

Referring now to FIG. 9 of the drawings, there is schematically illustrated the windings such as M of previously discussed gear motors GMl through GM4, the winding M of previously discussed gear motor HM, and previously discussed rotary union RU, cylinders HIOC and HUDC and the respectively associated piston rods PRll and PR2 of such cylinders. Also shown conven' tiorially in FIG. 9 are electric solenoid actuated and spring return two-position, fluid flow control valves VCV and HUDV, an electric solenoid actuated threeposition valve HIOV, and a programmer or timer TM including a drive motor M, an electrically energized clutch winding CW, and a plurality of electrical circuit controlling contacts IT through 8T which are actuated in a selected time sequence hereinafter discussed. Programmers or timers such as TM are well known in the art. A spring return manually actuated or depressed push button SPB is also shown in FIG. 9 for controlling an electrical circuit as hereinafter discussed. There is provided a suitable source of vacuum for supply through valve VCV and rotary union RU, and through shaft 61 to vacuum chuck VC, and a suitable source of pressurized fluid for supply through valves HIOV and HUDV to cylinders HIOC and HUDC, respectively. However, for purposes of simplification of the drawings said sources are not shown therein. There is also provided a source of electric energy of a suitable voltage and capacity for energization of the winding M of timer TM, of the windings M of gear motors GMl through GM4, of the winding M of gear motor HM, and of the windings Wll through W4 of the solenoids of valves HIOV, HUDV and VCV. However, also for purposes of simplification of the drawings, said source of electric energy is not shown therein but its positive and negative terminals are designated B and N, respectively.

OPERATIONAL EXAMPLE OF THE INVENTION For purpose of an operational example of the invention, it is assumed that the apparatus is in an initial condition in which piston rod PR1 is retracted within headin-and-out cylinder HIOC so that column or shaft 35 (FIGS. 1, 3 and 5) is in a rotative position such that arm 40 is positioned over platform 30 with the vertical centerline of the vacuum passage 61c in drive shaft 61 of vacuum chuck support assembly 55 and the center of vacuum chuck VC are vertically aligned with point B on surface 30c of plate 30b of platform 30 (FIG. 1). It is further assumed that piston rod PR2 of head-updown cylinder HUDC is retracted within such cylinder, that the aforesaid vacuum source has been activated to supply vacuum through valve VCV and rotary union RU and shaft 61 to vacuum chuck VC, and that the aforesaid source of pressurized fluid has been activated to supplysuch fluid to valves HIOV and HUDV and, thereby, temporarily maintain said piston rods PR1 and PR2 in their said retracted positions within their respective cylinders. Furthermore, all of the aforesaid windings of said motors and solenoids are assumed to be deenergized. Such conditions of the apparatus are shown in FIG. 9 and the following described operations are now performed.

At the article or panel receiving and pickup station, a television picture tube viewing panel such as P is placed on surface 300 of plate 30b of platform 30 (FIG.

1) and is positioned thereon so that two adjacent corners of the sealing edge of the panel are in contact with vertical surface 33b of plate 33a of jig or positioning device 33. Such positioning will cause the center point of the face plate portion of panel P to be precisely vertically aligned with said point B on surface 300 of plate 30b of platform 30 since the radius of said vertical surface 33b from said point B is equal to the radius of the corners of the sealing edge of panel P. It is pointed out, that in FIG. l, the orientation of panel P on said surface 300 is merely illustrative and that the center of the face plate portion of such panel will be vertically aligned with point B on surface 300 regardless of which two adjacent corners of the sealing edge of the panel are in contact with said surface 3312.

Following the above-discussed positioning of panel P, spring return push button SPB (FIG. 9) is depressed to initiate a cycle of operation of the apparatus. Such depression of the push button will close, at contacts a-b thereof, electrical circuits for the energization of the winding M of the motor of timer TM and of electric clutch winding CW of such timer, as well as electrical circuits for the energization of the windings such as M of gear motors GMl through GM4. It will be remembered that adjacent ones of gear motors GMl through GM4 rotate in opposite directions upon energization of the windings thereof and, for the purpose of the present operational example it will be assumed that gear motors GMll and GM3 rotate in clockwise directions and gear motors GM2 and GM4 rotate in counterclockwise directions. That is to say, diagonally oppositely disposed grinding wheels or disks 211 and 23 (FIG. I) are rotated in a first direction by their respectively associated gear motors and grinding wheels or disks 22 and 24 are rotated by their respective gear motors in a direction opposite to said first direction. By such opposite rotation of adjacent ones of the grinding wheels, linear translational forces, tended to be imparted to the sealing edge of a viewing panel when resting on the faces of the grinding wheels during a grinding operation on such sealing edge, are substantially counteracted and forces tending to cause linear translational movement of the viewing panel are thereby minimized.

The above-mentioned energization of winding M of the motor of timer TM and winding CW of the clutch of such timer causes contacts IT through 8T (FIG. 9) of the timer to close in a selected sequence to actuate the apparatus in the following manner.

Contact IT closes to maintain winding M and clutch winding CW, as well as the windings such as M of motors GMl through GM4 energized, and spring return push button SPB can then be released (no longer depressed) to permit the spring return feature of the push button to actuate contacts a-b thereof to their normally open condition.

- Contact 2T closes to energize solenoid winding W3 of valve HUDV against the pressure of spring S3 and such valve is actuated to supply pressurized fluid over conduit FC3 to the upper end of cylinder HUDC while conduit FC2 is connected through said valve to a fluid sink F82. Piston rod PR2 is, thereby, actuated downwardly to, in turn, actuate drive shaft 61 of vacuum chuck support assembly (FIGS. 3 and 6) downwardly and vacuum chuck VC correspondingly down ward so that the lower resilient brim 1133 of the vacuum chuck VC (FIG. 5) is in firm contact with the face plate portion of said panel P resting on surface 30c of platform 30. As previously mentioned vacuum is being supplied through rotary union RU to chuck VC at such time (FIG. 9) and, therefore, panel P is drawn into firm contact with brim 133 of the chuck. Contact 2T of timer TM then opens, winding W3 of valve HUDV is deenergized, and spring S3 of the valve returns it to its normal position so that the pressurized fluid is not supplied over conduitFC2 to the lower end of cylinder HUDC while conduit FC3 is connected to fluid sink FS2. Piston rod PR2 is thereby actuated upwardly to raise drive shaft 61 of vacuum chuck support assembly 55 and chuck VC. Panel P is thus picked up or raised from its position of rest on surface 30cof platform 30 until it is a selected distance above said surface and has at least cleared vertical surface 33b of plate 33a of positioning jig 33.

Contact 3T of timer TM closes and winding W2 of head-in-out valve HIOV is energized to actuate such valve to supply pressurized fluid over conduit FCS to the right hand end (viewing FIGS. 1 and 9) of head-inout cylinder I-IIOC while conduit FC4 is connected through said valve to a fluid sink FSl which may, if desired, be the same sink as previously mentioned fluid sink FS2. Piston rod PR1 is thus actuated out of its associated cylinder HIOC to rotate column or shaft 35 (FIGS. 1 and 5) and swing arm 39 so that the vertical centerline of the vacuum passage 61c in chuck support assembly 55 and the center of vacuum chuck VC move from the article or panel receiving and pickup station and through an arcuate path or line paralleling the aforesaid arcuate line or path BC (FIG. 1) until said centerline and center are vertically aligned with said point C at the article or panel grinding station where grinding wheels 21 through 24 are located, that is, so that said centerline of vacuum passage 61c and the center of vacuum chuck VC are vertically aligned with centerline AA (FIG. 5) extending vertically through the geometrical center of the horizontal plane of the faces 21a through 24a of grinding wheels or disks 21 through 24. Contact 3T subsequently opens, solenoid winding S2 of valve HIOV is deenergized and spring S1 of the valve returns it to its normal condition shown in FIG. 9.

Contact 4T of timer TM closes, winding M (FIG. 9) of gear motor HM (FIGS. 1, 3 and 9) is energized to impart rotation from drive shaft 51 of the motor to shaft 61 through connecting rod 106 and sleeve member 110 (FIG. 7) to shaft 61 and, thence, to vacuum chuck VC and panel P supported thereby.

Contact 5T of timer TM closes and solenoid winding W3 of valve HUDV is again energized to cause piston rod PR2 to lower vacuum chuck VC in the same manner as discussed therefor when such chuck was positioned at the article or panel receiving and pickup station. Vacuum chuck VC lowers panel P until the sealing edge of such panel rests on the faces 21a through 24a of rotating grinding wheels 21 through 24 as illustrated in FIG. 5. It should be pointed out that by using a plurality of grinding wheels for the grinding operations on the sealing edge of panel P, faster flat grinding of such edge is attained than if a single grinding wheel is employed for such a grinding operation. This is due to such sealing edge moving across the peripheral,

grinding edges of the grinding wheels as well as the grinding faces thereof. Furthermore, since the panel P and the grinding wheels are all rotated during a grinding operation, all of the grinding faces or surfaces of the wheels are used for grinding of the sealing edge of the panel and substantially uniform wear of said grinding faces or surfaces is attained. After a period of time allowed for said grinding operations, contact 5T of timer TM again opens to deenergize solenoid winding W3 of (valve HUDV and piston rod PR2 is again actuated up wardly to raise vacuum chuck VC and the supported panel P.

Contact 4T of timer TM opens to open the energizing circuit for winding M of gear motor HM and the rotation of such motor and, thereby, of chuck VC and panel P is terminated.

Contact 6T of timer TM closes and solenoid winding W1 of valve HIOV is energized to actuate such valve to supply pressurized fluid to fluid conduit FC4 and thence to the left hand side (FIGS. 1 and 9) of cylinder HIOC while fluid conduit FCS is connected through valve HIOV to fluid sink FSI. Piston rod PR1 of cylinder HIOC is again retracted within such cylinder and column or shaft 35 is thereby rotated to cause arm 39 to swing in the direction toward the article or panel receiving and pickup station, that is, in said arcuate path or line paralleling the arcuate path or line BC but in a direction from point C towards point B. Contact 6T subsequently opens to deenergize solenoid winding W! of valve HIOV and spring S2 of such valve returns it to its normal position shown in FIG. 9.

Contact 7T of timer TM closes to once again energize solenoid winding W3 of valve l-IUDV and vacuum chuck VC is thereby again lowered to lower panel P until the sealing edge of such panel rests on surface 306 of plate 30b of platform 30.

Contact 8T of the timer closes and solenoid winding W4 of valve VCV is energized to actuate such valve to interrupt the supply of vacuum therethrough to rotary union RU, vacuum passage 61c in shaft 61 and vacuum chuck VC. Panel P is, thus, released by the vacuum chuck.

Contact 7T of the timer opens and piston rod PR2 of cylinder HUDC is again retracted within such cylinder to raise vacuum chuck VC while leaving panel P on said surface 306.

Contact 8T of timer TM opens to deenergize solenoid winding W4 of valve VCV and such valve is actuated by spring S4 to again supply vacuum to rotary union RU and thence to vacuum chuck VC in preparation for pickup and transfer of another panel such as P whose sealing edge is to be ground.

Contact IT of timer TM opens to deenergize motor winding M and clutch winding CW of the timer. The deenergization of clutch winding CW immediately interrupts any further actuation of contacts IT through 8T of the timer TM. The above-mentioned opening of contact IT of the timer also interrupts the energizing circuits for the windings such as M of gear motors GMl through GM4 and the rotation of such motors and of grinding wheels 21 through 24 is terminated. The apparatus is now again in its initial condition and prepared for another cycle of operations thereof, that is, for the pickup and transfer of and grinding operations on the sealing edge of another panel delivered to platform 30 at the article receiving and pickup station. Such other cycle would, of course, be initiated in the same manner as that just described or discussed, that is, by the depressing or pushing of push button PSB until contact IT of timer TM closes.

Although there is herein shown and described only one form of apparatus for practicing the invention disclosed, it will be understood that such is not to be considered in any way limiting but that various changes and modifications may be made in the apparatus within the purview of the appended claims without departing from the spirit and scope thereof.

I claim:

1. Apparatus for transferring a rectangular viewing panel for a cathode ray or television picture tube be tween an article receiving and pickup station and a grinding station and flat grinding the annular sealing edge of the skirt portion of said panel, such apparatus comprising, in combination;

a. at said receiving and pickup station,

I. a platform having a horizontal upper surface for receivingand supporting said panel with said sealing edge contacting said upper surface, and

II. a jig on said upper surface of said platform for positioning of said panel with the vertical centerline of the face plate portion thereof in vertical axial alignment with a selected point on such upper surface, such jig including a circularly arcuate vertical surface having a horizontal radius corresponding to the largest radius of said annular sealing edge with the geometric center of the arc of such arcuate vertical surface coinciding with said selected point on the upper surface of said platform;

b. at said grinding station,

I. an even number of rotatably supported grinding wheels having upwardly disposed flat circular grinding faces of equal diameters and extending in a common horizontal plane, such faces radially symmetrically disposed about an axial centerline vertical to said plane and intersecting with a circularly arcuate line extending horizontally from said selected point on said upper surface of said platform, said grinding wheels being spaced from each other such that each said grinding face can at times contact all points on said sealing edge of said panel when such edge rests on such grinding faces with said vertical centerline of said face plate portion of the panel coinciding with said axial centerline,

II. first motor means for rotating adjacent ones of said grinding wheels in opposite directions when such motor means are energized; and

c. adjacent said pickup station and said grinding station,

I. a rotatable vacuum chuck for picking up and supporting said panel and means for supporting such chuck for vertical movement thereof and arcuate horizontal movement of the chuck through a circularly arcuate path of travel lying vertically above said circularly arcuate line and extending parallel therewith,

II. second motor means for rotating said chuck when such second motor means are energized, Ill. third motor means for vertically moving said chuck to lowered panel pickup and edge grinding positions, and to raised panel transfer positions accordingly as such third motor means are energized in first and second modes, respectively;

IV. fourth motor means for horizontally moving said chuck through said circularly arcuate path of travel to said pickup station and to said grinding station accordingly as such fourth motor means are energized in first and second modes, respectively, and

V. valve means for supplying and terminating nega tive pressure to said chuck accordingly as such valve means are deenergized and energized, respectively.

2. Apparatus in accordance with claim l and in which said grinding wheels are fourin number with the centers thereof coinciding with the four corner points of a square and with the peripheral edge of each said grinding face lying closely and correspondingly adja cent each such edge of a pair of the other grinding faces.

3. Apparatus in accordance with claim 1 and in which said first and second motor means are electric motors, said valve means is a solenoid energized valve, and said third and fourth motor means are pressurized fluid cylinders and associated pistons.

4. Apparatus in accordance with claim 1 and further including a control system for sequentially,

A. energizing said first motor means,

B. energizing said third motor means in said first mode thereof to lower said vacuum chuck into contact with the face plate portion of said viewing panel delivered to said pickup station and positioned thereat with the vertical centerline of such face plate portion in vertical axial alignment with said selected point on said upper surface of said platform,

C. energizing said third motor means in said second mode thereof,

D. energizing said fourth motor means in said second mode thereof,

E. energizing said second motor means,

F. energizing said third motor means in said first mode thereof,

G. energizing said third motor means in said second mode thereof and deenergizing said second motor means,

H. energizing said fourth motor means in said first mode thereof,

1. energizing said third motor means in said first mode thereof,

J. energizing said valve means,

K. energizing said third motor means in said second mode thereof to raise said vacuum chuck in preparation for pickup, transfer and grinding of the sealing edge of another viewing panel delivered to and positioned at said pickup station following the removal of the prior panel from such station, and

L. deenergizing said valve means.

5. Apparatus in accordance with claim 2 and in which said first and second motor means are electric motors, said valve means is a solenoid energized valve, and said third and fourth motor means are pressurized fluid cylinders and associated pistons.

6. Apparatus in accordance with claim 2 and further including a control system for sequentially,

A. energizing said first motor means,

B. energizing said third motor means in said first mode thereof to lower said vacuum chuck into contact with the face plate portion of said viewing panel delivered to said pickup station and positioned thereat with the vertical centerline of such face plate portion in vertical axial alignment with said selected point on said upper surface of said platform,

C. energizing said third motor means in said second mode thereof,

D. energizing said fourth motor means in said second mode thereof,

E. energizing said second motor means,

F. energizing said third motor means in said first mode thereof,

G. energizing said third motor means in said second mode thereof and deenergizing said second motor means,

H. energizing said fourth motor means in said first mode thereof,

1. energizing said third motor means in said first mode thereof,

J. energizing said valve means,

K. energizing said third motor means in said second mode thereof to raise said vacuum chuck in preparation for pickup, transfer and grinding of the sealing edge of another viewing panel delivered to and positioned at said pickup station following the removal of the prior panel from such station, and

L. deenergizing said valve means.

7. Apparatus in accordance with claim 3 and further including a control system for sequentially,

A. energizing said'first motor means,

B. energizing said third motor means in said first mode thereof to lower said vacuum chuck into contact with the face plate portion of said viewing panel delivered to said pickup station and positioned thereat with the vertical centerline of such face plate portion in vertical axial alignment with said selected point on said upper surface of said platform,

C. energizing said third motor means in said second mode thereof,

D. energizing said fourth motor means in said second mode thereof,

E. energizing said second motor means,

F. energizing said third motor means in said first mode thereof,

G. energizing said third motor means in said second mode thereof and deenergizing said second motor means,

H. energizing said fourth motor means in said first mode thereof,

1. energizing said third motor means in said first mode thereof,

J. energizing said valve means,

K. energizing said third motor means in said second mode thereof to raise said vacuum chuck in preparation for pickup, transfer and grinding of the sealing edge of another viewing panel delivered to and positioned at said pickup station following the removal of the prior panel from such station, and

L. deenergizing said valve means.

8. Apparatus in accordance with claim 5 and further including a control system for sequentially,

A. energizing said first motor means,

B. energizing said third motor means in said first mode thereof to lower said vacuum chuck into contact with the face plate portion of said viewing panel delivered to said pickup station and positioned thereat with the vertical centerline of such face plate portion in vertical axial alignment with said selected point on said upper surface of said platform,

C. energizing said third motor means in said second mode thereof,

D. energizing said fourth motor means in said second mode thereof,

E. energizing said second motor means,

F. energizing said third motor means in said first mode thereof,

1 G. energizing said third motor means in said second mode thereof and deenergizing said second motor means,

H. energizing said fourth motor means in said first mode thereof,

1. energizing said third motor means in said first mode thereof,

. J energizing said valve means,

K. energizing said third motor means in said second mode thereof to raise said vacuum chuck in preparation for pickup, transfer and grinding of the sealing edge of another viewing panel delivered to and positioned at said pickup station following the removal of the prior panel from such station, and

L. deenergizing said valve means. 

1. Apparatus for transferring a rectangular viewing panel for a cathode ray or television picture tube between an article receiving and pickup station and a grinding station and flat grinding the annular sealing edge of the skirt portion of said panel, such apparatus comprising, in combination; a. at said receiving and pickup station, I. a platform having a horizontal upper surface for receiving and supporting said panel with said sealing edge contacting said upper surface, and II. a jig on said upper surface of said platform for positioning of said panel with the vertical centerline of the face plate portion thereof in vertical axial alignment with a selected point on such upper surface, such jig including a circularly arcuate vertical surface having a horizontal radius corresponding to the largest radius of said annular sealing edge with the geometric center of the arc of such arcuate vertical surface coinciding with said selected point on the upper surface of said platform; b. at said grinding station, I. an even number of rotatably supported grinding wheels having upwardly disposed flat circular grinding faces of equal diameters and extending in a common horizontal plane, such faces radially symmetrically disposed about an axial centerline vertical to said plane and intersecting with a circularly arcuate line extending horizontally from said selected point on said upper surface of said platform, said grinding wheels being spaced from each other such that each said grinding face can at times contact all points on said sealing edge of said panel when such edge rests on such grinding faces with said vertical centerline of said face plate portion of the panel coinciding with said axial centerline, II. first motor means for rotating adjacent ones of said grinding wheels in opposite directions when such motor means are energized; and c. adjacent said pickup station and said grinding station, I. a rotatable vacuum chuck for picking up and supporting said panel and means for supporting such chuck for vertical movement thereof and arcuate horizontal movement of the chuck through a circularly arcuate path of travel lying vertically above said circularly arcuate line and extending parallel therewith, II. second motor means for rotating said chuck when such second motor means are energized, III. third motor means for vertically moving said chuck to lowered panel pickup and edge grinding positions, and to raised panel transfer positions accordingly as such third motor means are energized in first and second modes, respectively; IV. fourth motor means for horizontally moving said chuck through said circularly arcuate path of travel to said pickup station and to said grinding station accordingly as such fourth motor means are energized in first and second modes, respectively, and V. valve means for supplying and terminating negative pressure to said chuck accordingly as such valve means are deenergized and energized, respectively.
 2. Apparatus in accordance with claim 1 and in which said grinding wheels are four in number with the centers thereof coinciding with the four corner points of a square and with the peripheral edge of each said grinding face lying closely and correspondingly adjacent each such edge of a pair of the other grinding faces.
 3. Apparatus in accordance with claim 1 and in which said first and second motor means are electric motors, said valve means is a solenoid energized valve, and said third and fourth motor means are pressurized fluid cylinders and associated pistons.
 4. Apparatus in accordance with claim 1 and further including a control system for sequentially, A. energizing said first motor means, B. energizing said third motor means in said first mode thereof to lower said vacuum chuck into contact with the face plate portion of said viewing panel delivered to said pickup station and positioned thereat with the vertical centerline of such face plate portion in vertical axial alignment with said selected point on said upper surface of said platform, C. energizing said third motor means in said second mode thereof, D. energizing said fourth motor means in said second mode thereof, E. energizing said second motor means, F. energizing said third motor means in said first mode thereof, G. energizing said third motor means in said second mode thereof and deenergizing said second motor means, H. energizing said fourth motor means in said first mode thereof, I. energizing said third motor means in said first mode thereof, J. energizing said valve means, K. energizing said third motor means in said second mode thereof to raise said vacuum chuck in preparation for pickup, transfer and grinding of the sealing edge of another viewing panel delivered to and positioned at said pickup station following the removal of the prior panel from such station, and L. deenergizing said valve means.
 5. Apparatus in accordance with claim 2 and in which said first and second motor means are electric motors, said valve means is a solenoid energized valve, and said third and fourth motor means are pressurized fluid cylinders and associated pistons.
 6. Apparatus in accordance with claim 2 and further including a control system for sequentially, A. energizing said first motor means, B. energizing said third motor means in said first mode thereof to lower said vacuum chuck into contact with the face plate portion of said viewing panel delivered to said pickup station and positioned thereat with the vertical centerline of such face plate portion in vertical axial alignment with said selected point on said upper surface of said platform, C. energizing said third motor means in said second mode thereof, D. energizing said fourth motor means in said second mode thereof, E. energizing said second motor means, F. energizing said third motor means in said first mode thereof, G. energizing said third motor means in said second mode thereof and deenergizing said second motor means, H. energizing said fourth motor means in said first mode thereof, I. energizing said third motor means in said first mode thereof, J. energizing said valve means, K. energizing said third motor means in said second mode thereof to raise said vacuum chuck in preparation for pickup, transfer and grinding of the sealing edge of another viewing panel delivered to and positioned at said pickup station following the removal of the prior panel from such station, and L. deenergizing said valve means.
 7. Apparatus in accordance with claim 3 and further including a control system for sequentially, A. energizing said first motor means, B. energizing said third motor means in said first mode thereof to lower said vacuum chuck into contact with the face plate portion of said viewing panel delivered to said pickup station and positioned thereat with the vertical centerline of such face plate portion in vertical axial alignment with said selected point on said upper surface of said platform, C. energizing said third motor means in said second mode thereof, D. energizing said fourth motor means in said second mode thereof, E. energizing said second motor means, F. energizing said third motor means in said first mode thereof, G. energizing said third motor means in said second mode thereof and deenergizing said second motor means, H. energizing said fourth motor means in said first mode thereof, I. energizing Said third motor means in said first mode thereof, J. energizing said valve means, K. energizing said third motor means in said second mode thereof to raise said vacuum chuck in preparation for pickup, transfer and grinding of the sealing edge of another viewing panel delivered to and positioned at said pickup station following the removal of the prior panel from such station, and L. deenergizing said valve means.
 8. Apparatus in accordance with claim 5 and further including a control system for sequentially, A. energizing said first motor means, B. energizing said third motor means in said first mode thereof to lower said vacuum chuck into contact with the face plate portion of said viewing panel delivered to said pickup station and positioned thereat with the vertical centerline of such face plate portion in vertical axial alignment with said selected point on said upper surface of said platform, C. energizing said third motor means in said second mode thereof, D. energizing said fourth motor means in said second mode thereof, E. energizing said second motor means, F. energizing said third motor means in said first mode thereof, G. energizing said third motor means in said second mode thereof and deenergizing said second motor means, H. energizing said fourth motor means in said first mode thereof, I. energizing said third motor means in said first mode thereof, J. energizing said valve means, K. energizing said third motor means in said second mode thereof to raise said vacuum chuck in preparation for pickup, transfer and grinding of the sealing edge of another viewing panel delivered to and positioned at said pickup station following the removal of the prior panel from such station, and L. deenergizing said valve means. 